Secondary turns set the rectified reservoir valley against the required minimum, so the margin moves from failing to just meeting to clearing the boundary. The rows are ideal transformer and rectifier ledgers; real supplies depend on winding resistance, transformer regulation, diode drops, ripple current, mains variation, reservoir capacitance, load changes, and measurement uncertainty.
Transformer turns are carried through rectifier loss and reservoir valley acceptance. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Secondary turns 2 sets reservoir margin
Primary source stays 24 V with 6 primary turns. Secondary turns 2 produce valley 4 V against the 8 V minimum, so margin is negative 4 V.
4V−8V=−4V⇒fail
Secondary turns 3 sets reservoir margin
Primary source stays 24 V with 6 primary turns. Secondary turns 3 produce valley 8 V against the 8 V minimum, so margin is 0 V.
8V−8V=0V⇒pass
Secondary turns 4 sets reservoir margin
Primary source stays 24 V with 6 primary turns. Secondary turns 4 produce valley 12 V against the 8 V minimum, so margin is 4 V.